Statistical Comparative Study of the Trend and Variation of Meteorological Parameters in Abeokuta, South-West Nigeria

Abstract

This study focuses on the statistical comparative study of the trend and variation of meteorological parameters covering a 10 year period (2001-2010) in the capital and largest city of Ogun State, Abeokuta, southwest region of Nigeria. The analyzed meteorological parameters were: wind speed, vapour pressure, relative humidity, temperature, sunshine and rainfall covering 10 years. The calculated coefficient of variation (CV) for sunshine (22.78%), wind speed (21.55%), and rainfall (99.12%) is a proof of exceedance of variability of threshold of 10% while the CV calculated for air temperature (5.74%), relative humidity (4.52%) and vapour pressure (5.22%) show no significant variability. Significance test of meteorological parameters’ trend reveals a notable reduction in the values of vapour pressure, air temperature and relative humidity. It is, however, difficult to argue for a well-defined change in most of the meteorological parameters based on the monthly time series analyses performed in this work. Only wind speed shows a statistically significant increasing trend during the period of observation at 1% significance level. The trend revealed by rainfall and sunshine is statistically not significant. ANOVA test of significant difference among meteorological parameters show a p-value (Sig.) of 0.000 is an indication of the significant difference in the analyzed mean monthly coefficient of variation for the meteorological parameters under study. The Tukey’s multiple pair comparisons test, however, show that there is a significant difference between the mean monthly CV of rainfall–sunshine, rainfall-vapour pressure, rainfall-wind speed, rainfall-air temperature and rainfall-relative humidity. At the significance level of 5%, the calculated mean monthly CV of rainfall is significantly different from the mean monthly CV of other climatic parameters.